Phil and Sal race each other for 100 yards. Sal wins by 10 yards. They decide
to race again, but this time, to even things up, Sal begins 10 yards behind the start
line. Assuming that both run with the same constant speed as before, who wins?

Sal wins again. In the first race she ran 100 yards in the time it took Phil to run
90. Therefore, in the second race, after Phil has gone 90 yards, Sal will have gone
100, so she will be alongside him. Both will have 10 more yards to go. Since Sal is
the faster runner, she will finish before Phil.